بررسي ويژگي هاي فيزيكوشيميايي و مكانيكي نان تست فاقد گلوتن حاوي صمغ هاي عربي و دانه خرنوب

Application of xanthan, inulin, tapioca and pre-gelatinized starch in different production condition on the physicochemical, rheological, sensorial and shelf life of low fat mayonnaise

نان به عنوان يكي از ارزان ترين منابع انرژي در تغذيه مردم دنيا نقش حياتي دارد. اما اين نان ها قابل استفاده براي بيماران سلياكي نيست، بنابراين توليد نان بدون گلوتن براي بيماران سلياكي كه از حساسيت به گلوتن رنج مي برند ضروري به نظر مي رسد. هدف از اين تحقيق توليد و بررسي خصوصيات فيزيكوشيميايي و مكانيكي نان تست فاقد گلوتن حاوي صمغ هاي عربي و خرنوب است. به اين منظور نان تست با فرمولاسيوني ثابت و با تغيير غلظت صمغ ها (خرنوب و عربي 0، 1 و 2 درصد و يك نمونه تركيبي از هر دونوع صمغ با غلظت 1 درصد) تهيه شد. نتايج نشان داد كه در اثر افزايش غلظت صمغ ها، به طور معني داري ميزان رطوبت و درصد حفظ آن طي روزهاي مورد بررسي افزايش داشت. همچنين در اثر افزايش غلظت صمغ ها به طور معني داري حجم مخصوص افزايش پيدا كرد. بررسي خصوصيات مكانيكي نتايج نشان داد كه سختي و نيروي شكست در اثر افزايش غلظت صمغ عربي و دانه خرنوب كاهش و چسبندگي و فنريت در طي دوره نگهداري افزايش معني داري داشت(0.05>p).

Mayonnaise, as an oil in water emulsion, with pH value of lower than 4.1, is one of the oldest man made emulsions and is consumed at high value in the world and Iran. Nowadays, gums are used at high levels to stabilize of mayonnaise and changing rheological properties of it. The aim of this study was the effects of gums as fat replacers, include xanthan, inulin, tapioca and pre-gelatinized starch at concentrations of 0.2, 0.3 and 0.4% at different agitation speed on stability of low-fat, physico-chemical and rheological properties of mayonnaise. The results indicated that the type of gum, gum concentration and agitation speed had no significant effect on pH and acidity of the mayonnaise samples (p>0.05). The highest viscosity was due to xanthan gum sauce and there was no significant difference between pre-gelatinized starch, tapioca and inulin (p>0.05). Also samples with 2500 rpm had highest viscosity and the viscosity of samples with 1500 and 1700 stirrers was not significantly different. Increasing the concentration of gum from 0.2 to 0.4 increased viscosity, but no significant difference was observed between the samples (p>0.05). In terms of the stability of the emulsion, the sample containing xanthan at a concentration of 0.2 and the circumference of the 2500 stirrer showed the highest stability. In terms of different sensory characteristics, xanthan and starch pre-gelatinous were ranked first.